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Publish Events to Kafka

MinIO supports publishing bucket notification events to a Kafka service endpoint.

MinIO relies on the Shopify/sarama project for Kafka connectivity and shares that project’s Kafka support. See the sarama Compatibility and API stability section for more details.

Add a Kafka Endpoint to a MinIO Deployment

The following procedure adds a new Kafka service endpoint for supporting bucket notifications in a MinIO deployment.

Important

This procedure requires restarting all minio server processes associated to the deployment at the same time. There is typically a brief period of time during which API operations are interrupted or may fail.

Applications using an S3-compatible SDK with built-in retry logic or which implement manual retry logic typically experience no notable interruption in services. For applications which cannot use retry-logic, consider scheduling a maintenance period to minimize interruption of services while performing this procedure.

Prerequisites

Kafka Minimum Versions and Supported Versions

MinIO relies on the Shopify/sarama project for Kafka connectivity and shares that project’s Kafka support. See the sarama Compatibility and API stability section for more details.

MinIO mc Command Line Tool

This procedure uses the mc command line tool for certain actions. See the mc Quickstart for installation instructions.

1) Add the Kafka Endpoint to MinIO

You can configure a new Kafka service endpoint using either environment variables or by setting runtime configuration settings.

MinIO supports specifying the Kafka service endpoint and associated configuration settings using environment variables. The minio server process applies the specified settings on its next startup.

The following example code sets all environment variables related to configuring a Kafka service endpoint. The minimum required variables are MINIO_NOTIFY_KAFKA_ENABLE and MINIO_NOTIFY_KAFKA_BROKERS:

set MINIO_NOTIFY_KAFKA_ENABLE_<IDENTIFIER>="on"
set MINIO_NOTIFY_KAFKA_BROKERS_<IDENTIFIER>="<ENDPOINT>"
set MINIO_NOTIFY_KAFKA_TOPIC_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_KAFKA_SASL_USERNAME_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_KAFKA_SASL_PASSWORD_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_KAFKA_SASL_MECHANISM_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_KAFKA_TLS_CLIENT_AUTH_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_KAFKA_SASL_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_KAFKA_TLS_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_KAFKA_TLS_SKIP_VERIFY_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_KAFKA_CLIENT_TLS_CERT_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_KAFKA_CLIENT_TLS_KEY_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_KAFKA_QUEUE_DIR_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_KAFKA_QUEUE_LIMIT_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_KAFKA_VERSION_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_KAFKA_COMMENT_<IDENTIFIER>="<string>"
  • Replace <IDENTIFIER> with a unique descriptive string for the Kafka service endpoint. Use the same <IDENTIFIER> value for all environment variables related to the new target service endpoint. The following examples assume an identifier of PRIMARY.

    If the specified <IDENTIFIER> matches an existing Kafka service endpoint on the MinIO deployment, the new settings override any existing settings for that endpoint. Use mc admin config get notify_kafka to review the currently configured Kafka endpoints on the MinIO deployment.

  • Replace <ENDPOINT> with a comma-separated list of Kafka brokers. For example:

    "kafka1.example.com:2021,kafka2.example.com:2021"

See Kafka Service for Bucket Notifications for complete documentation on each environment variable.

MinIO supports adding or updating Kafka endpoints on a running minio server process using the mc admin config set command and the notify_kafka configuration key. You must restart the minio server process to apply any new or updated configuration settings.

The following example code sets all settings related to configuring an Kafka service endpoint. The minimum required setting is notify_kafka brokers:

mc admin config set ALIAS/ notify_kafka:IDENTIFIER \
   brokers="<ENDPOINT>" \
   topic="<string>" \
   sasl_username="<string>" \
   sasl_password="<string>" \
   sasl_mechanism="<string>" \
   tls_client_auth="<string>" \
   sasl="<string>" \
   tls="<string>" \
   tls_skip_verify="<string>" \
   client_tls_cert="<string>" \
   client_tls_key="<string>" \
   version="<string>" \
   queue_dir="<string>" \
   queue_limit="<string>" \
   comment="<string>"
  • Replace IDENTIFIER with a unique descriptive string for the Kafka service endpoint. The following examples in this procedure assume an identifier of PRIMARY.

    If the specified IDENTIFIER matches an existing Kafka service endpoint on the MinIO deployment, the new settings override any existing settings for that endpoint. Use mc admin config get notify_kafka to review the currently configured Kafka endpoints on the MinIO deployment.

  • Replace ENDPOINT with a comma separated list of Kafka brokers. For example:

    "kafka1.example.com:2021,kafka2.example.com:2021"

See Kafka Bucket Notification Configuration Settings for complete documentation on each setting.

2) Restart the MinIO Deployment

You must restart the MinIO deployment to apply the configuration changes. Use the mc admin service restart command to restart the deployment.

Important

MinIO restarts all minio server processes associated to the deployment at the same time. Applications may experience a brief period of downtime during the restart process.

Consider scheduling the restart during a maintenance period to minimize interruption of services.

mc admin service restart ALIAS

Replace ALIAS with the alias of the deployment to restart.

The minio server process prints a line on startup for each configured Kafka target similar to the following:

SQS ARNs: arn:minio:sqs::primary:kafka

You must specify the ARN resource when configuring bucket notifications with the associated Kafka deployment as a target.

3) Configure Bucket Notifications using the Kafka Endpoint as a Target

Use the mc event add command to add a new bucket notification event with the configured Kafka service as a target:

mc event add ALIAS/BUCKET arn:minio:sqs::primary:kafka \
  --event EVENTS
  • Replace ALIAS with the alias of a MinIO deployment.

  • Replace BUCKET with the name of the bucket in which to configure the event.

  • Replace EVENTS with a comma-separated list of events for which MinIO triggers notifications.

Use mc event list to view all configured bucket events for a given notification target:

mc event list ALIAS/BUCKET arn:minio:sqs::primary:kafka

4) Validate the Configured Events

Perform an action on the bucket for which you configured the new event and check the Kafka service for the notification data. The action required depends on which events were specified when configuring the bucket notification.

For example, if the bucket notification configuration includes the s3:ObjectCreated:Put event, you can use the mc cp command to create a new object in the bucket and trigger a notification.

mc cp ~/data/new-object.txt ALIAS/BUCKET

Update a Kafka Endpoint in a MinIO Deployment

The following procedure updates an existing Kafka service endpoint for supporting bucket notifications in a MinIO deployment.

Important

This procedure requires restarting all minio server processes associated to the deployment at the same time. There is typically a brief period of time during which API operations are interrupted or may fail.

Applications using an S3-compatible SDK with built-in retry logic or which implement manual retry logic typically experience no notable interruption in services. For applications which cannot use retry-logic, consider scheduling a maintenance period to minimize interruption of services while performing this procedure.

Prerequisites

Kafka Minimum Versions and Supported Versions

MinIO relies on the Shopify/sarama project for Kafka connectivity and shares that project’s Kafka support. See the sarama Compatibility and API stability section for more details.

MinIO mc Command Line Tool

This procedure uses the mc command line tool for certain actions. See the mc Quickstart for installation instructions.

1) List Configured Kafka Endpoints In The Deployment

Use the mc admin config get command to list the currently configured Kafka service endpoints in the deployment:

mc admin config get ALIAS/ notify_kafka

Replace ALIAS with the alias of the MinIO deployment.

The command output resembles the following:

notify_kafka:primary tls_skip_verify="off"  queue_dir="" queue_limit="0" sasl="off" sasl_password="" sasl_username="" tls_client_auth="0" tls="off" brokers="" topic="" client_tls_cert="" client_tls_key="" version=""
notify_kafka:secondary tls_skip_verify="off"  queue_dir="" queue_limit="0" sasl="off" sasl_password="" sasl_username="" tls_client_auth="0" tls="off" brokers="" topic="" client_tls_cert="" client_tls_key="" version=""

The notify_kafka key is the top-level configuration key for an Kafka Service for Bucket Notifications. The brokers key specifies the Kafka service endpoint for the given notify_kafka key. The notify_kafka:<IDENTIFIER> suffix describes the unique identifier for that Kafka service endpoint.

Note the identifier for the Kafka service endpoint you want to update for the next step.

2) Update the Kafka Endpoint

Use the mc admin config set command to set the new configuration for the Kafka service endpoint:

mc admin config set ALIAS/ notify_kafka:<IDENTIFIER> \
   url="https://kafka1.example.net:9200, https://kafka2.example.net:9200" \
   exchange="<string>" \
   exchange_type="<string>" \
   routing_key="<string>" \
   mandatory="<string>" \
   durable="<string>" \
   no_wait="<string>" \
   internal="<string>" \
   auto_deleted="<string>" \
   delivery_mode="<string>" \
   queue_dir="<string>" \
   queue_limit="<string>" \
   comment="<string>"

The notify_kafka brokers configuration setting is the minimum required for a Kafka service endpoint. All other configuration settings are optional. See Kafka Service for Bucket Notifications for a complete list of Kafka configuration settings.

3) Restart the MinIO Deployment

You must restart the MinIO deployment to apply the configuration changes. Use the mc admin service restart command to restart the deployment.

Important

MinIO restarts all minio server processes associated to the deployment at the same time. Applications may experience a brief period of downtime during the restart process.

Consider scheduling the restart during a maintenance period to minimize interruption of services.

mc admin service restart ALIAS

Replace ALIAS with the alias of the deployment to restart.

The minio server process prints a line on startup for each configured Kafka target similar to the following:

SQS ARNs: arn:minio:sqs::primary:kafka

3) Validate the Changes

Perform an action on a bucket which has an event configuration using the updated Kafka service endpoint and check the Kafka service for the notification data. The action required depends on which events were specified when configuring the bucket notification.

For example, if the bucket notification configuration includes the s3:ObjectCreated:Put event, you can use the mc cp command to create a new object in the bucket and trigger a notification.

mc cp ~/data/new-object.txt ALIAS/BUCKET